Laser printer and copier toner cartridges are made from materials that may be safely and economically recycled, but only when suitable processes are developed and utilized. Unfortunately today, toner cartridge recycling operations are not as safe or as environmentally friendly as they should be. The current processes are often uneconomical and may not survive without subsidies. This state of affairs exists because there are issues concerning health, safety and economics in the existing processes that need to be improved.
Safety and health issues arise when residual toner in cartridges is liberated and becomes airborne, during the recycling process. The amount of airborne toner must be monitored and controlled in order to avoid fires and explosions and to limit exposure of personnel to respiratory complications from inhalation of toner dust. Economic issues arise from the high cost of operations that provide the requisite safety and that produce clean and pure streams of recovered materials that must be produced in order to earn the best salvage prices.
Currently, the most common method of recycling toner cartridges is to remove residual toner, demolish the cartridges by crushing or shredding and then sorting the resultant materials into reusable categories. The salvaged material categories generally include major amounts of a few types of engineering plastics, toner, steel and aluminum and minor amounts of a few other types of metal and plastic. The materials are sorted by operations that vary from totally manual to totally automated identification and separation systems. Properly cleaned and separated materials can be sold at prices that offset a significant part of the cost of the recycling operation.
Recycling of printer toner cartridges can be hazardous. The hazard primarily results from the requirement to remove and process residual toner. Toner consists mostly of plastic plus small amounts of carbon black or other colorants and minor amounts of additives that enhance the toner's storage and performance characteristics, e.g. to make the toner ferromagnetic, etc. Toner components are generally prepared as finely divided powders that can become airborne if disturbed. Once airborne, toner may be inhaled by exposed and unprotected personnel. Though toner materials are generally considered non-toxic to humans, if inhaled, the finely powdered materials can go deeply into one's lungs where, over time, they may cause irritation, breathing discomfort, or even more serious respiratory problems.
Even so, the greatest hazard may not be to health but rather safety. Safety is at issue because toner is flammable and it is readily suspended in air in concentrations sufficient to support combustion. In that state it can be easily ignited and result in serious explosions or fires.
Some recyclers are managing health and safety hazards by providing operating personnel respirators and by removing toner from cartridges before crushing or shredding. These recyclers often use the toner handling procedures developed by toner cartridge manufacturers. While these procedures have been proven effective, they typically involve expensive equipment and high operation and maintenance costs. These costs often cannot be recovered from the sale of the recycled materials and the operations have to be subsidized to survive.
Other recyclers have developed an automated method that removes and collects the residual toner in an inert atmosphere. This method reduces labor costs but introduces costs for the inert gases consumed in the process as well as higher costs for equipment and maintenance. Both methods capture toner in filters that also require regular replacement and disposal of the spent filters and dry toner.
The safest and least expensive toner cartridge recycling method that has been developed avoids handling dry powdered toner entirely; U.S. Pat. No. 7,999,012 filed Oct. 20, 2008, to Lamphere. It processes toner cartridges in a non-flammable fluid environment. This method captures most of the toner in the process fluid. The fluid is then filtered and returned to the process.
The toner captured in the process fluid is removed by filters as a damp sludge or cake. Toner is completely safe to handle in this form and thus it can be delivered into a wider range of applications than dry powdered toner.